InGaAs based devices are great complements to silicon for CMOS, as they provide an increased carrier saturation velocity, lower operating voltage and reduced power dissipation. In this work we show that
 In0.75Ga0.25As quantum wells with a high mobility, 15 000 to 20 000 cm2/V.s at ambient temperature, show
 an InAs-like phonon with an energy of 28.8 meV, frequency of 232 cm-1 that dominates the polar-optical mode scattering from ∼
 70 K to 300 K. The optical phonon frequency is insensitive to the carrier density modulated with a surface
 gate or LED illumination. We model the electron scattering mechanisms as a function of temperature and
 identify mechanisms that limit the electron mobility in In0.75Ga0.25As quantum wells. Background impurity
 scattering starts to dominate for temperatures <100 K. In the high mobility In0.75Ga0.25As quantum well,
 GaAs-like phonons do not couple to the electron gas unlike the case of In0.53Ga0.47As quantum wells.